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Cytological and genetic evaluation of anther culture-derived doubled haploids in barley

100%

Szarejko I., Fakl D. E., Janusz A., Nabialkowska D.

Journal of Applied Genetics

1997

vol. 38

issue 4

437-452

Gametoclonal variation among anther culture-derived plants of three barley genotypes was estimated on the basis of cytological analysis (DH1, DH2 generation), observation of morphological variants (DH2, DH3) and chlorophyll mutation test (DH2, DH3). Individual head rows were grown in the field to detect possible chimeric structure of regenerants and to assess the number of variants and mutations in each line. Spontaneously doubled plants were the most frequent class (70%) among regenerants and almost 90% of them were completely fertile. There was a difference in proportion of haploids produced by different genotypes, but the highest frequency observed did not exceed 21%. The remaining regenerants were tetraploid, and contained chromosomal mutations or chimeras. In total, there were about 15% of polyploids and plants carrying chromosomal aberrations (translocations, inversions) among DH1 individuals. The changes in chromosome number and structure were the main source of observed variation. The level of gene mutation induced in vitro was relatively low. No more than 1% of microspore-derived plants expressed visible morphological changes in DH2 progeny. Only two morphological variants derived from the Bruce cultivar proved to be homozygous mutants (dwarf type) stable up the to third generation. The frequency of DH plants carrying chlorophyll mutation was 5.8%, but most of them (82%) were chimeric and had only a small mutation sector. The level of gametoclonal variation depended on the donor plant genotype. The highest proportion of variants and mutations was observed among DH plants derived from the Bruce cultivar, while the lowest was recorded among plants regenerated from anther culture of the doubled haploid line H930-36. Mechanisms leading to the observed variation and implications resulting from the presented experiments concerning implementation of anther culture in barley breeding were discussed. It was concluded that this method resulted in a high frequency of spontaneous doubling, a low frequency of genetic changes, and being less time and effort-consuming than the 'Bulbosum' technique, can be applied to most barley breeding programs.

Different level of point mutation and chromosomal changes among regenerants in tissue culture of Arabidopsis thaliana (L.) Heynh.

100%

Nabialkowska D., Szarejko I., Siwinska D.

Biotechnologia

2004

issue 2

79-85

Using the regeneration method described by Feldman and Marks (1986), the level of somaclonal variation (frequency of gene mutations and chromosomal changes) was determined in A. thaliana regenerants from root and shoot explants. The explants were regenerated via indirect organogenesis with callus stage. The level of embryo lethal mutations and changes in chromosome number were estimated in R2 generative progeny of regenerants, and confirmed in R3 generation. The frequency of R1 plants carrying gene mutations was similar for all types of explants and on average it reached 8.3%, however only 47% of R1 plants showed the presence of the same embryo mutation in R2 and R3 generation. The frequency of embryo-lethal mutants, among 25 571 embryos tested, was 1.7%, while 0.08% embryos carried chlorophyll mutations. The plants with increased chromosome number were observed in the progeny of 32.2 % R1 regenerants, i.e. with eight times higher frequency than regenerants carrying gene mutations. All polyploid plants were obtained from shoot explants, while regenerants from roots carried normal diploid number of chromosomes. The observed changes in chromosome number were discussed in relation to the different content of DNA in root and shoot cells of A. thaliana.

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1 Biotechnologia

1 Journal of Applied Genetics

1 2004

1 1997

2 Nabialkowska D.

2 Szarejko I.

1 Fakl D. E.

1 Janusz A.

1 Siwinska D.

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Cytological and genetic evaluation of anther culture-derived doubled haploids in barley

Different level of point mutation and chromosomal changes among regenerants in tissue culture of Arabidopsis thaliana (L.) Heynh.